The media measurement auditor was initially concerned about the ability to measure viewability, but said yesterday that “there has been a significant improvement in the percentage of ads for which the viewable status can be determined, and the percentage of ads for which viewability is undetermined has dropped precipitously from earlier levels”.

“In short,” the MRC said, “the limitations on viewability measurement that initially led MRC to issue its advisory have been largely ameliorated today.”

The exception is viewability measurements for video advertising. MRC is advising an additional 90-day gating period before viewable video impressions are used as a trading currency, on the grounds that the final parameters for defining a viewable video ad were only determined in January.

MRC said the additional 90 days, “will allow time for additional analyses of the impact of the shift to viewable impressions for video, and is in line with similar periods of impact data that MRC generally looks for in comparable measurement transitions in other media”.

The Interactive Advertising Bureau (IAB) welcomed the lifting of the advisory as “a momentous occasion for consumers, brands, and publishers”.

“This shift in media currency will help brands connect with engaged consumers, and do the kind of multi-platform campaigns across media properties they’ve been eager to do almost since the internet was born,” said IAB.

Working with MRC, the IAB has released Viewable Impression Measurement Guidelines, which state that 50% of pixels must be in the viewable portion of an internet browser for a minimum of one continuous second to qualify as a viewable display impression.

“The shift from a ‘served’ impression to a viewable impression standard will provide marketers with a more accurate way to quantify their investment and deliver increased value for all parties involved in brand advertising,” the IAB said.

Alongside the lifting of the advisory, MRC has also accredited 11 organisations for their viewability measurements. One of those companies, Integral Ad Science, announced yesterday that it would partner with Nielsen to add its viewability methodology to the global rollout of Nielsen’s Online Campaign Ratings service. The combined service is currently under MRC review.